Overweight/Obesity and Monoclonal Gammopathy of Undetermined Significance.

BACKGROUND: Obesity and high body mass index (BMI) are associated with increased incidence of multiple myeloma (MM). MM usually evolves from a precursor asymptomatic disease, namely monoclonal gammopathy of undetermined significance (MGUS). MGUS progresses to MM at a 1% annual rate; however, risk factors predisposing to MGUS are not completely understood. We conducted a systematic review to assess the relationship between obesity and high BMI with MGUS prevalence and progression to MM. To our knowledge, this is the first systematic review evaluating the role of obesity in MGUS.

PATIENTS AND METHODS: We searched the Medline database and ClinicalTrials.gov for studies investigating BMI and obesity association with MGUS incidence and progression. The algorithm consisted of a predefined combination of the words "obesity," "obese," "body mass index," "overweight," "diet," "nutrition," "food," "dietary," "adiponectin," "monoclonal gammopathy," and "MGUS".

RESULTS: Overall, 12 articles were retrieved, including 11 eligible articles and 1 clinical trial. More than 57,068 patients were evaluated in this systematic review. Discrepancies between the identified studies were noted. Multiple studies support the notion that obesity or high BMI are positively linked to MGUS prevalence and transition to MM. In contrast, other studies revealed no such association. Visceral adipose tissue metabolic activity and decreased adiponectin concentrations were identified as biomarkers of MGUS progression to MM.

CONCLUSION: Obesity and increased BMI seem to be implicated both in MGUS development and progression to MM. Further studies should be designed to confirm this hypothesis.